mains now to be seen occupy the same site in which they grew, and that the theory that they were floated as snags into their present position has no evidence whatever to support it. An objection urged, that in some cases parts of the rootlets are broken off short (which, it was said, ought not to be the case if they are in situ), was shewn by Mr. Reade to be explained by the fact, that the wood being now very rotten is broken off along with the peat surrounding it by the action of the sea, but that where the peat is undenuded the rootlets can be traced in it entire.

Mr. Reade also pointed out that the evidence of the Forest Beds at Leasowe has a bearing on a controversy that has been going on regarding a much older deposit, that of the Cromer Forest-Bed underlying the Boulder Clay, and in which trees have been discovered in situ. Some geologists assert that these were drifted down as snags, and deposited in their present position by a river which they identify with the Rhine; yet if the evidence in our local case points to the undoubted existence of a Forest-Bed in situ, in main particulars agreeing with the published descriptions of the Cromer Forest-Bed, it is only reasonable to suppose that the conditions in both cases have been similar, and that the manner of their formation was identical.

Evening Field Meeting, June 29th, 1883.

Held at Tranmere. Conducted by Mr. WILLIAM H. MILES. Sections of Drift Deposits in the Excavations for the Mersey Railway, at the foot of Holt Hill, were inspected, by permission of Mr. James Prentice, Manager. In the Borough Road, another cutting was visited, showing angular and sub-angular blocks of sandstone, intermixed with sand lying above the Pebble Beds.

LIVERPOOL GEOLOGICAL ASSOCIATION.

Ordinary Meeting, July 2nd, 1883.

Held at the Free Library, the Vice-President MR. CHARLES E. MILES, in the Chair.

Mr. W. R. Cooper, B.A. was elected a Member.

Proposed as Members:

Messrs. T. M. Johnson, 60, Lord Street; John Nicholls, 11, Chatham Place, Edge Hill; Thomas Maguire, 108, Landseer Road, Everton; and the Rev. Wm. Paton, Mossgiel House, New Ferry, Cheshire.

DONATIONS.

"The Scientific Roll," Edited by Alexander Ramsay, F.G.S.-presented by the Editor; "Drift Beds of the North-West of England and North Wales," by T. Mellard Reade, F.G.S.,-presented by the Author; "Report and Proceedings of the Belfast Naturalists' Field Club, 1881-82;" Report" 1882, of the Liverpool Science Students' Association; "Proceedings," No. 6, of the Liverpool Astronomical Society,-presented by the respective Societies.

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The following Paper was read:

"ON THE PREPARATION OF ROCKS FOR
MICROSCOPICAL EXAMINATION,"

(PRINCIPALLY WITH REFERENCE TO THE SEDIMENTARY ROCKS.) BY HENRY C. BEASLEY.

I propose in the present paper to give an account of the methods I have myself found most convenient for preparing specimens of rocks for examination under the microscope, with such appliances as may be readily obtained at a small cost; and I shall presume, at the outset, that the object is the examination of specimens collected in the field by the practical geologist, and not the manufacture of microscope slides on an extensive scale.

(Vol. III.-Session 1882-88.-No. 10.

I will, in the first instance, take for example a piece of ordinary carboniferous limestone, as being a rock of average hardness and compactness, and afterwards shew the somewhat different treatment required by the softer rocks on the one hand, and the harder rocks on the other.

1. The first operation is to procure a thin flake of the rock, say about an inch across this can often be done by a smart blow of a hammer near the edge, but it can generally be insured by holding the hand specimen of the rock in one hand on a cold chisel fixed to a block of wood, or on the sharp end of a geological hammer, and striking it a sharp blow with a hammer with the other hand.

2. The next operation is to grind one side quite flat. The quickest way of doing this is by rubbing it on a flat piece of hard sandstone, about 14 ins. by 10 ins. sprinkled with coarse emery powder, and kept well wet. A flat piece of iron, or a piece of plate glass is very handy, in case you are travelling about, instead of the flat sandstone, but it does not grind so rapidly, as of course the grinding is in that case done by the emery alone.

3. Having got a flat surface right across the flake, the next process is to remove the roughness. For this I generally use an emery hone of medium fineness, but a piece of plate glass with fine emery is very good. Great care must be taken that none of the grains of coarser emery used in the previous process adhere either to the specimen or to the plate glass, otherwise deep scratches will result, which will require a great deal of labour to get rid of; the specimen must therefore be carefully washed between each operation. I prefer the emery hone to the plate of glass, as there are fewer loose particles of emery about.

4. As soon as you have rubbed it as smooth as possible on the emery hone, wash it carefully, and then rub it with a somewhat circular motion on a water of Ayr stone, and if you are careful not to have any bits of grit or emery about, you will in a minute or so have a surface free from scratches. Instead of the water of Ayr stone, another plate of glass may be used

with very fine emery powder. The glass has the advantage of preserving an even surface, whereas the emery stone and the water of Ayr stone will wear into hollows, however careful you may be to distribute the friction over the whole surface; but they can be readily ground smooth on the sandstone slab used for the first process, and will at the same time tend to produce an even surface on that, and I thiuk that the little trouble is quite compensated by the absence of annoyance from the dirt and grit that always is liable to get about, when emery powder is used. Having freed the surface from scratches, it will be advisable to examine the specimen under the microscope as an opaque object. By wetting the surface and throwing a strong light upon it through a bulls' eye condenser, you will readily make out a good deal of its structure, and that of the minute fossils it contains. Some rocks lend themselves much more readily than others to this mode of examination. If this seems

likely to be the case in this instance, it will be well to proceed to polish the specimen. In most cases a thin film of moisture will render the features very distinct, and for rocks that will not readily take a polish, a good way to examine them is to cover the smooth surface with a thin coat of Canada balsam, and cover it with a thin piece of glass. Of course, however, the result is not nearly so satisfactory as when a fine polish has been given to the surface; and this may generally be done by getting as fine a surface as possible on a german hone, or some similar stone, and then polishing it upon a piece of coarse felt well sprinkled with the very finest "putty powder" (muriate of tin) obtainable. It should be kept just damp during the operation. Do not let the felt at all saturated with water.

get

5. We will now return to the piece reserved for a transparent section, and which has been rubbed down to a tolerably smooth surface. We next procure a piece of plate glass 1 in. or 2in. square, and on to this we fasten the smooth side of our specimen. The best substance for this purpose is Canada balsam; it can be procured at any chemists, and is generally sold in too soft a condition for use for this purpose, so it will

"

be necessary to heat it in an open vessel (I generally use a porcelain dish) for some hours, taking care that it does not boil, or the bubbles formed will be a great trouble in succeeding operations. The balsam should be tried from time to time. by taking out a small portion on a steel rod, knitting needle, or knife, and cooling it, and when it is hard enough to resist the pressure of the thumb nail, it should be at once removed, as if it is further heated it will become too brittle to use.

Heat the specimen and the piece of glass until as hot as you can bear to touch with the finger, then place a portion of the hardened balsam on the piece of glass, where it will melt, and press the flat surface of the specimen firmly upon it, moving it a little to get the melted balsam evenly spread beneath it to expel any bubbles that may have formed.

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20

When the balsam has thoroughly set, you can grind the stone away with your coarsest emery till it is about 1 in. thick, the square of glass serving as a convenient handle; then it will be advisable to use the finer emery or hones as directed before. It is important now to get as perfectly level a surface as possible, so care must be taken to hold the specimen firmly in one position while using the finer hones. By the time all the scratches are removed the stone will be about 1 in. thick, and it will be advisable to put a fine polish upon it, unless there are any interstices in it, which would hold the putty powder, in which case it is better to finish it on a plain piece of leather. The specimen by this time will probably be somewhat less in diameter than it was, but if not more than an inch in one direction it will make a very good slide, and of course the larger the better, if well done; but practically you will find that it is better to divide it into smaller pieces, therefore just mark it across with a knife, scratching it as deeply as you can, and dividing it into portions about in.

square.

You now take the square of glass and scrape off all the balsam you can that may surround the specimen, and then warm it, and when it is thoroughly warm a gentle but firm lateral pressure with a blunt instrument, say the handle of